Single break oil circuit breaker structure having dual valve structure



April 1l, 1967 J, R, MCCLQ'UD ET AL 3,313,901

, SINGLE BREAK OIL CIRCUIT BREAKER STRUCTURE HAVING DUAL VALVE STRUCTURE Filed NOV. 20. 1964 4 SheeS-Sheet 1 205 22? Z2? ,Z/ n 4 2/34 l l ZZ/ April ll, 1967 "yt R, MCCLOUD ET ALv 3,313,901

SINGLE BREAK OIL CIRCUIT BREAKER STRUCTURE HAVING DUAL VALVE STRUCTURE NOV. 20 4 Sheets-Sheet 2 Ff-E. E.

BY ye/v! .a Maca/WMM April 11, 1967 J. R. MccLoUD ETAL 3,313,901

SINGLE BREAK OIL CIRCUIT BREAKER STRUCTURE HAVING DUAL VALVE STRUCTURE Filed Nov. zo. 1964 4 sheets-sheet a FG-.5. IFE-1.5..

a, O O eff prll 11, 1967 J, R MCCLOUD ETAL SINGLE BREAK. OIL CIRCUIT BREAKER STRUCTURE HAVING DUAL VALVE STRUCTURE Filed Nov. 20. 1964 4 Sheets-Shee. 4

v which is engaged by a movable rod-type contact.

United States Patent O 3,313,901 SINGLE BREAK OHL CIRCUIT BREAKER STRUC- TURE HAVING DUAL VALVE STRUCTURE James R. McCloud, Burbank, and Lorne D. McConnell,

Sierra Madre, Calif., assignors to I-T-E Circuit Breaker Company, Philadelphia, Pa., a corporation of Perm- Sylvania Filed Nov. 20, 1964, Ser. No. 412,662 3 Claims. (Cl. 200-150) This invention relates to oil circuit breakers, and more p speciiically relates to a novel group of features for an improved single break oil circuit breaker interrupter and lresistor structure therefor.

Interrupters for oil circuit breakers are well known to those skilled in the art. Such interrupters are generally shown in copending application Serial No. 67,125, tiled November 3,'1960, entitled Tank Structure For Oil Circuit Breaker, in the name of James R. McCloud (now abandoned), and assigned to the `assignee of the present invention, and include an interrupter structure which is immersed in oil and which has a stationary Contact therein As the movable contact is moved to a disengaged position, the arc drawn within the interrupter chamber is extinguished by the flow of gaseous arc products and Iclean oil through the arc and out through exhaust ports in the interrupter chamber. In order to aid in the interruption of the arc, it is common practice to connect a resistor in parallel with the main contacts. This resistor circuit must be opened when the main movable contact moves to its fully disengaged position so that the current llow through the resistorwill be interrupted.

A first feature of the present invention is directed to a novel pump structure for causing oil ilow during low power arc interruption wherein a novel check-valve arrangement is provided which normally permits circulation of oil through the pump piston and into the interrupter. This novel valve arrangement includes a rst annular valve disk carried by the main piston which is movable into sealing engagement with a series of openings in the main piston. Thus, during low arc current interruption, the novel annular valve closes off the ports in the cylinder so that the piston can properly operate. Under normal conditions, however, oil ilow can easily take place through this series of openings so that improved cooling of the interrupter is achieved.

Moreover, during high current arcing conditions, the pressure generated within the interrupter container serves immediately to force a second check valve disk upwardly to seal off channels between the piston and interrupter to prevent the application of excessive pressure to the piston.

Accordingly, an important object of the present invention is to provide a novel pump arrangement for an oil immersed interrupter structure.

Another object of this invention is to provide a novel means for permitting circulation of oil through an interrupter structure, and to automatically seal the oil passages in the piston during interruption conditions.

Another object of this invention is to provide a novel piston arrangement which is automatically operated under spring 4biasing means when a movable Contact of an interrupter structure is moved to a disengaged position.

A still further object of this invention is to provide aV novel oil check-valve arrangement.

The present invention further provides a novel valve for the exhaust ports of the interrupter structure. That is to say, valves are often used which are in communication with the venting ports of an interrupter chamber wherein the valves seal the ports until a sufficient pressure build-up is provided for an oil piston or by other 3,313,901 Patented Apr. ll, 1967 means. The present invention provides a novel valve structure which is of low mass and provides large area venting with short travel. Moreover, the novel valve structure of the invention is inexpensive, easily assembled and easily replaced.

Each of the ports associated with the valve structure of the invention form two paths leading to two ports in the interrupter container. The ports are flared out to permit easy expansion of gases and other arc products passing through the ports. The two passages then join in a common passageway located internally of the interrupter, this passageway receiving the novel valve of the invention which is of triangular form so that it can block the passage between the common channeland the two outlet channels. If desired, the valve may be metallic or non-metallic, and is biased into sealing engagement with the main channel by a metallic or non-metallic biasing spring. Y

The seal ports, as previously indicated, are enlarged Y openings and preferably are positioned to direct the flow of emitted oil and gas in directions away from the nearest point of the tank which contains the interrupters and the oil in which the interrupters are immersed.

Accordingly, another important object of this invention is to provide a novel sealing valve for the port of an interrupter which provides large area venting with short travel.

Another object of this invention is to provide a novel valve for the ports of an interrupter structure which are of low mass.

A still further object of this invention is to provide a novel valve for the ports of an interrupter structure which is inexpensive, easy to assemble and easily replaced.

A still further object of this invention is to provide a novel valve for the ports of an interrupter structure wherein the ports increase in area as they approach the outside of the confining tube.

As a still further feature of the invention and in order to insure that pressure can be built up within the interior of the interrupter chamber, a novel seal is further provided around the moving contact rod to prevent loss of oil and oil pressure during opening operation of the interrupter. The novel seal of the invention is so arranged that it fits snugly around the movable contact rod, but is laterally movable within the bottom plug of the interrupter. Accordingly, the opening in the bottom of the tube Will be sealed about the movable contact rod although the movable contact rod is permitted to have lateral motion to allow for misalignment between the contact` rod and the opening in the bottom of the interrupter tube.

Thus, another important object of the invention is to provide a novel seal about the movable contact rod of an interrupter structure to permit pressure build-up within the interrupter during interrupting conditions.

Another object of this invention is to provide a novel seal for the movable contact of an interrupter structure which permits lateral movement of the contact rod.

As indicated in` the foregoing, resistors are commonly provided in parallel with the main contacts of an interrupter structure. A further feature of the novel invention provides a n-ovel mounting structure and assembly for a resistor to be connected in parallel with an interrupted structure. More specifically, the novel resistor structure includes a novel pair of floating contacts at either Y end of the resistor tube which are held assembled by a is to provide -a novel arrangement for mounting the resistor to be connected in parallel with the main contacts of an oil circuit breaker interrupter.

Another object of this invention is to provide a novel construction for the resistor of an oil circuit breaker interrupter.

A still further object of the invention is to vprovide novel floating contact arrangement which is held in place by snap-rings for the easy assembly of a complete resistor.

As is well known, and as previously indicated, there is usually misalignment between the movable contact which is carried from a lift-rod and cross-bar assembly in lthe Well-known manner and the opening at the bottom ofl'the interrupter. The present invention further provides a novel structure for securing the movable contact rod to its cross-,bar so that the contact may be adjusted on ythe cross-bar withvrespect to the opening in the interrupter. This novel arrangement includes a locking means for the adjustably positioned contact rod and a carrying block for receiving the contact rod.

Accordingly, a still further object of this invention is toprovide a novel connection between the contact rod of an oil circuit breaker and the cross-bar.

A'further object of this invention is to provide a novel locking means for adjustably connecting a lift-rod to a cross-bar assembly and the contact rods to the ends of the cross-bar assembly.

These and other objects of this invention will become apparent from the following description when taken in connection with the drawings, in which:

FIGURE 1 is a side cross-sectional view of an interrupter structure constructed in accordance with the present invention.

FIGURE 2 is a top plan view of FIGURE 1 seen from lines 2 2 in FIGURE 1.

FIGURE 3 is a cross-sectional view o1 FIGURE 1 across lines 3 3 in FIGURE 1.

FIGURE 4 is a cross-sectional view of FIGURE 1 .across lines 4 4 in FIGURE 1. l

FIGURE 5 shows a cross-sectional view of FIGURE 1 across the lines Srl-57a in FIGURE 1 for the right-hand side of FIGURE 5 and across the lines 5b 5b in FIG- URE 1 for the left-hand side of FIGURE 5.

FIGURE 6 is an exploded perspective View of the port valve structure. Y

FIGURE 7 is a partial front plan view of the interrupter container of FIGURE 1 to illustrate the ports in the container.

FIGURE 8 is a cross-sectional view of FIGURE 1 taken across the lines 8 8 in FIGURE 1.

FIGURE 9 is a partial cross-sectional View of the resistor upper support cap taken across the lines 9 9 in FIGURE 2.

FIGURE 10 is a cross-sectional view of the resistor lower support structure taken across the lines 1.0 10 in FIGURE 4.

FIGURE 11 is an exploded perspective view of the resistor contact structure.

Referring now to the gures, an interrupter structure is shown for an oil circuit breaker of the type shown in copending application Serial No. 67,125 Where the interrupter structure of the figures will be immersed in oil within an oil lled tank (not shown) and will be carried from suitable insulator bushings which enter the tank. Thus, the interrupter, as shown in FIGURES 1 and 2, is provided with an upper conductive Cap assembly Zt which is securable to a suitable adapter structure 21 shown in dotted lines in FIGURE 1, which is, in turn, connected to the end of an insulator bushing. Note -that the upper portion of cap has a smooth circular opening 22 which is best suited for high voltage purposes.

The cap 20 which is cast of a suitable metallic material serves as the support for the interrupter structure generally shown by numeral 23 in FIGURE 1 which contains the various components of the interrupter equipment.

The interrupter structure 23 more specifically includes an insulation container 24 which may be formed of any suitable material such as fiber glass which has an enlarged upper section 25 (FIGURE 1) that receives a mounting ring 26. The mounting ring 26 then has a plurality of bolt holes therein which receive respective bolts such as bolt 27 in FIGURE 1, and bolts 3@ through 34 in FIG- URE 3, which extend upwardly through a conductive pressure pad 28 and into suitably tapped openings in the bottom of cap 2d. The member 2S and the bottom of cap 211 further serve to receive the stationary contact structure generally indicated by numeral 34 in FIGURE 1. More specifically, the stationary contact structure includes a conductive hub 35 which carries a plurality of spring biased contact fingers about its periphery. FIG- URE 1 shows two of these contact iingers 36 and 41,

whileA the left-hand side of FIGURE 5 shows the manner' in which similar contact iingers 37 through 4@ surround and are carried by the contact hub 35. The contact finger 41 of FIGURE 1 is longer than the other of the contact iingers and serves as the arcing contact.

Each of the various contact fingers are carried from the hub 3S, as shown in FIGURE 1, by conductive straps such as straps 42 and 43 for contacts 36 and 41 respectively which are secured to the Contact hub by screws 44-45 and 45-47 respectively which are threaded to suitably tapped openings in the hub 35.

Each of the contact fingers are also biased inwardly by suitable `biasing leaf springs such as leaf springs 48 and `4.9 in FIGURE 1 which bear upon insulated buttons 50 and 51-52 for contacts 36 and'41 respectively. These insulation buttons prevent the formation of a conductive path through the biasing springs so -that the springs will not be heated by the conduction of current therethrough.

28 and into threaded engagement with a suitably threaded opening in cap 20.

The stationary contact structure receives a co-operating movable contact rod 60 which may have an arcing tip 61 of suitable arc-resistant material secured to the conductive lower body of the rod 60. The rod 60- is then secured to a cross-'bar 62 which is carried, in turn, from a lift-rod in the usual manner, and as shown, for example, in copending application Serial No. 67,125, and as will be described more fully hereinafter.

The cross-bars 62 are movable from a lower position at which the contact tip 61 is completely removed from the interrupter to the position shown in FIGURE 1 where the contact rod 61B is in engagement with the stationary contact structure. During movement off Contact rod 60 to the disengaged position, an arc will be drawn directly from tip 61 to arcing contact finger 41. In order to eX- tinguish this arc, the interrupter container 24 has therein a series of plates. More specifically, the interrupter container 24'has contained therein a spacing cylinder 70, the upper end of which is engaged by plate 28 through the gasket 70a. The lower end of cylinder 70, which may be of any suitable phenolic-type material, then seats upon and compresses the stack of plates 71 through 77 against a further spacing cylinder 78. The cylinder 78 then seats upon bottom plate '79 which is placed atop the throat bushing 80 which is captured in the necked-down portion S1 of the container 24.

Each of plates 72, and 77 have the arrangement shown in FIGURE 1a and have a central opening 60a for receiving the Contact rod 60 and an opening 91a forV receivingrod 91. They also have keying openings 72a and 72b for receiving keying pins and through holes 82a and 82h for receiving alignment rods such as rod 82.

The upper plate 71 has the shape shown in FIGURE 1b and includes rod opening 91b for receiving rod 91 and a keyhole opening 60b for receiving contact rod 60 andcontact finger 41.v Alignment rod openings 82C and 82d are also provided for alignment rods 82. It will also be noted that two oily passages 71a and 71b also passr through plate 71.

The plates 71 through 77, plate 79 and throat bushing 80 are then aligned. with respect to one another by suitable alignment rods such as rod 82 (FIGURE 1 and the right-hand sideof FIGURE 5) and a similar rod 83 (left-hand side of FIIGURE 5). 'Ihe plates 7 1 through 77 also contain aligned openings therein which receive an insulation tube 90 through. w'hich an insulation rod 91 passes. The insulation rod 91 is terminated at its top and bottom by suitable ttings 92 and 93, the rod 91 beingl axially movable within insulation tube 90. The lower fitting 92 is then engaged by an operating rod 94 which is connected to the cross-bar 62, while the upper iitting 93 engages the lower end of a piston 95.

More particularly, rod 91 is yformed of a densitied Wood. The iittings 92 and 93 are of steel and are secured to r-od 91 over a tapered surface by a suitable epoxy cement.y Key anchors are formed in the cemented joint by placing grooves suehv as goove 91a around the tapered wood ends and filling them with epoxy before connecting the littingsto the rody 91. Preferably, escape openings such as openings 92a and-93a are formed in fittings 92 and 93 respectively to permit escape of excess glue.

The piston. 95 is then movable Within la cylinder 96, as shown in FIGURES 1 and 4. The lower portion of piston 95 then carries a movable disk-shaped check-valve 110 (FIGURE 1) which is movable into sealing engagement with respect to the openings such as openings 100 through 11019 in piston 95.k The check-valve 110 is retained on piston 95 by a'y suitable sleeve 111 which is threaded onto the threads 112 on the bottom of piston 95. Once member 111 is in place, the threads 112 are preferably' staked to prevent movement of member 111.

.Concentriccompression springs 113 and 1.14, as shown in FIGUR-E 1, are then captured. between the interior of piston 95 and surface 115 formed within cap 2t)l to normally bia-s piston` 95 downwardly; This movement is restrained by rods 91 and 94 when the cross-bar 62 is in the position shown.

V'l'he piston 95 serves -as a pump for providing high pressure Within the interior off the interrupter during low current interrupting conditions. To this end, it should be remembered that the volume beneath` piston 95 is lled' with oil;` A plurality of channels 120 and 1-21 communicate with the volume beneath piston 95 and the internal volume off the interrupter. Otherl similar channels' 122 through 125 are shown in FIGURE 4. Note that` a further channel 128 (FIGURE l) permits the introduction of oi-l into the interrupter structure from the area external thereof.

A second check-Valve 126 isthen formed on a reduced diameter portion of contact hub 35, as shown in FIGURE 1, check-valve 126 being movable into sealing engagement with openings 120 through 125 in plate 28 when the pressure within the interrupter chamber exceeds the pressure below piston 95.

As previously indicated, it. is necessary that there be ports in the walls of. container 24 through which gas and oil may be ejected during interrupting conditions. Mo-reover, it is desirable to provide a valve in such ports so thatvent-ing will not occur until some predetermined pressure is built. up within the container (for low current switching). p

,To this en'd, plates 74 and 76, which are each arranged as illustrated'y in FIGURES l, 5 and 6, are provided with a V-shaped notch `1140l which communicates with channel 141 which, in tu-rn, communicates with the interior oilcontaining volume 142. of e'aeh of the plates. The V- shaped notch 149 in each of plates- 74 and 76` then receives an insert such as insert 150 which defines first and second. channels 151 and 152 respectively in each of plates 74 and 76. A similar insert. 153 is shown in FIGURE 1` for the plate 76. The inserts 150 and 153l are then held in 6 place by suitable pins such as pins and 161 in FIG- URE 3 which enter. into plates 75 and 77` respectively.

For purposes of pre-alignment of the various plates, a similar pin arrangement keys plates 72 and 7'3 with respect to one another s'o that they areY automatically' properly aligned.

Each of inserts 150 and 1'53 are then provided with a suitable notch such as notch which receives compres# sion springs such as springs 166 and 167 for inserts 150 and 153 respectively Each of springs 166 and 167 are then secured to a V-shaped, preferably ncnametallic, valve such as valves 168 and 169 respectively. These valves are then bia-sed into engagement with the main channel of their respective interrupter, as shown for the enga-gement between valve 168 in the channel 141 in FIGURE 3. Note lthat the adjacent plates 73 and 75 serve to seal the upper and lower portions of channel 141 in FIGURE 3 by overlapping the notch opening 14 at the point Where valve 16-8 is positioned.

The channels 151 and 152 then communicate with ports 170 and 171 respectively in container 24 (FIGURE 7) and are normally isolated from main channel 141.

A similar port arrangement including ports 170a and.

171a (FIGURE 7) will, of course, be found Afor plate 66 with its two respective channels and two respective ports being normally isolated from the interior of container 24.

Moreover, it will be noted from FIGURE 5 that the ports 170 and 171 in container 24 llare outwardly so that the port' area increases as the outer diameter of container 24 is approached.. By using a dual port arrangement, the direction of gas blast through channels such as channels 151 and 152 may be directed toward those portions of the main tank which are furthest removed from the interrupter structure.

In order to maintain internal pressure within container 24 during line switching or low current interrupting conditions, it has been further found desirable to provide a seal about the movable contact rod 60. This sealL has previously been avoided because of unavoidable misaligr1 ment between the contact rod and the center of the interrupter container.

In accordance with the present invention, however, a

shelf (FIGURE 1) is provided in the throat bushing 80 which receives lan internal gasket ring 191. The internal diameter of ring 191 forms a snug iit on rod 60 which permits axial motion of rod 60, yet forms a good pressure seal to the rod 60. Moreover, the outer diameter of ring 191 has a smaller diameter than the diameter of shelf 191i.` Accordingly, lateral movement of ring 191 along with contact rod 619 is permissible. The upper and lower surfaces of ring 191 are then confined between.

are necessary to interrupt the resistive current path after v the interrupter has successfully operated.

In accordance with the present invention, a novel resistor arrangement is provided which includes two paralflel connected resistors 20d and 201 (FIGURES 1, 2, 4 and 8). Resistors 200 and 201 are identical and their structure is shown in cross-section in FIGURE 1 for resistor 200.

Referring now to FIGURES 1 and 2, the resistor 21N) is mounted between an -upper mounting assembly which includes a conductive cap 202 (FIGURE 9) and a lower insulation support structure 203 (FIGURES 4 and 10). The upper support .structure 202 is bolted to the upper cap 20 as by bolts such as bolt 204.V Each of resistors 200 and 201 are then received in openings 205 and 205a respectively in cap 202. A similar arrangement is provided for lower support 203 where the support 20-3 is suitably secured to container 24 as by suitable bolts 210 and 211, shown in FIGURE 4, which are threaded into the throat bushing 80.

Each of the resistors .such as resistor 200- are then formed of an insulation tube 212 which has therein a stack of resistor elements such as resistor elements 213, 214 and 215. These resistor elements may be of any desired type well known to those skilled in the art, and are stacked to a desired height and are of a diameter to meet particular operating characteristics required.

The ends of the stack of resistor elements terminate in conductive was'hers 216 and 217 respectively which receive compression springs 218 and 219V respectively. The compression springs 218 and 219 are then contained by floating hollow contacts 220 and 221 respectively. The floating contacts 220 and 221 each have flanges 222 'and 223 respectively which, after assembly of all of the various elements of the resistor within the tube 212, are captured by snap-rings 224 and 225 respectively. The floating contact 220 is biased into engagement with conductive support 202 to form one terminal connection for the resistor, while the lower floating contact 221 is biased toward engagement with contact strip 230 (FIGURES l and 4) which is captured within insulation support 203.

It is to be noted that in the mounting arrangement shown, the resistor casing 212 is directly received. It is, however, possible to form contacts 220 and 221 with lug-shaped ends so they may serve as both the mechanical support and electrical terminal for the resistor. The lower end of the resistors 200 and 201 are connected to the contact rod 60 as shown in FIGURES 8 and 11. The resistors 200 and 201 are connected in parallel by virtue of their common connection at the top through conductive support 202 and at the bottom through conductive strip 230 carried in insulation support 203 (FIG- URE 10).

The conductive strip 230, as shown in FIGURE 8, is electrically connected to a conductor 240 which is, in turn, connected to a conductive bolt 241 which is threaded into throat bushing 80. The Ibolt 241 terminates in a conductive block 242 and pulls block 242 into engagement with a conductive shunt jumper 243. The conductive jumper 243 has a U-shape, as shown, and .its opposite ends terminate on movable contact members 244 and 245 respectively, shown in FIGURES l and4.

The central opening in the throat bushing lwhich receives conductive blocks 244 and 245 also receives insert 245a which has cut-out sections 246 and 247 for blocks 244 and 245 respectively which limit the motion of conductive blocks or contacts 244 and 245 toward and away yfrom one another. Biasing springs 248 and 249 are then captured in the contacts 244 and 245 respectively with the opposite ends of springs 24S and 249 bearing against the internal walls of the opening in throat bushing 80. Thus, the contacts 244 and 245 are biased toward engagement with contact rod 60, thereby connecting the bottom o-f resistors 200 and 201 to the contact rod 60.

Note that when the contact rod 60 is moved to its disengaged position and withdrawn |from the bottom of the throat bushing 80, the inward motion of contacts 244 and 245 is limited by the stop coniiguration of sections 246 and 247, as well as by the projecting section of member 242.

VFrom t'he foregoing it is believed clear that the resistors are now connected in parallel with the main contacts where, for example, the upper end of resistors 200 During operation of the circuit interrupter to the disengaged position, it is believed further clear that the resistors 200 and 201 remain connected in parallel with the main interrupting contacts until, after interruption is successfully accomplished and tip 611 of contact rod 60 leaves throat bushing 80,- the currentpath through the resistors will be interrupted at contacts 244 and 24S.

As a further feature of the invention, I have provided a novel manner for the adjustable connection between contact rod 60 and the cross-rod 62. Moreover, a similar type connection may be made between the lift-rod and the cross-bar 62.

-More particularly, and as shown in FIGURES l, 1c and ld, conductive cross-bars 30-0 and 301 have key Ways 302 and 303 therein whichreceive keys 304 and 3015 extending from block 306'. Block 306 is slotted by slot 307 and has threaded openings 30S and 309 therein forV Moreover, the key way connection between the blocky 306 and cross-bars 300 and 3011 permits Va limited lateral adjustment before locking 'by bolts 310 and 311.

The manner in which the novel interrupter operates is described in the following with the novelV interrupter broken into various sections, as indicated.

A.-OIL CHECK-VALVE ARRANGEMENT In order to operate the circuit interrupter of FIGURE 1 to the disengaged position from the engaged position shown, the cross-bar 62 is moved downwardly. During this downward motion, the contact rod 60 moves out of enga-gement with the various contacts carried from contact hub 3-5, and an arc is drawn from arcing contact nger 41.

It is necessary now to generate sucient pressure within the interior of the container 24 so that arc products and oil will be caused to flow through the arc and out of the various ports such as ports 170* and 171 in the container wall.

When interrupting arcs of low power, insufficient pressure .may be generated to effectively interrupt the arc. Accordingly, and particularly for the interruption of such low power arcs, the piston serves as a pump tov generate the pressure required to move oil and arc products from the volume beneath piston 95 through opening 120 through 125 and into the interior of container 24. This high pressure oil is then used to extinguish low current arcs.

In the event that a high current arc is drawn, then very high pressures are generated within container 2 4.V This normally tends to force oil back through openings through 124, theretb-y forcing piston 95 upward. y

In order to prevent this action which could damage piston 95, the novel check-valve arrangement includes the further check-valve 126 which is. forced upwardly by high pressure oil within the interrupter container 24 created by high current arcs, thereby closing off openings 120 through and thus sealing the volume beneath piston 95 from the interrupter tube.

Note, however, that during normal operating conditions, both check-valves 111 and 126 will be open. Accordingly, a path is formed for the natural ilow of oil through the interrupter, for example, due to convection so that continuous cooling by convection can occur.

9 B.FLOATING SEAL FOR CONTACT ROD rupter is still maintained, since the gasket 191 snugly fits around contact rod 60.

C.-VALVE STRUCTURE FOR VENTING PORTS Further associated with the problem of permitting a build-up of suicient pressure for the interruption of low current arcs, the venting ports such as ports 170l and 171 are normally closed Iby valves such as valves 168 and 169". During a low current arc, no venting occurs until the pressure within the chamber becomes suiciently high to overcome the biasing force of springs 166 and 167. As soon as this pressure, which is a pressure suiciently high to cause effective interruption of the arc, is reached, the valves 168 and 169| are moved outwardly so that venting can proceed from the interior of container 24 to the exterior channels such as channels 151 and 152.

Note that a single triangularly shaped valve controls the communication to each of the two exhaust channels in any one plane. Furthermore, the valve arrangement is such that a large area is exposed for venting action responsive to a relatively short travel of the valve members. Moreover, the novel manner of assembly of the valves clearly permits inexpensive manufacturing techniques along With ease of assembly and maintenance.

By using two blast channels in each plane and causing them to increase in area as the ports near the outside of the tube, the outwardly directed jet of arc products may now have a lower velocity with a decreased resistance to flow. Therefore, lower reaction forces occur by the outward taperin-g of the exhaust ports such as ports 170 and 171.

Note also that the arrangement shown provides an nherent stop surface for the movement of valves 168 and 169 wherein the motion of the valves is rigidly stopped when they engage their respective inserts 150 and 153;

D RESISTOR AND MOUNTING STRUCTURE THEREFOR The novel arrangement and mounting for the resistors 200 and 201 insure positive electrical contact under eX- treme vibration. Thus, all points of electrical contact include high compression springs such as springs 218 and 219 for contactsr22tl and 221 respectively, and similar compression springs 248 and 249 which bias contacts 244 and 245 respectively into engagement with contact 60.

Moreover, the novel mounting arrangement is such that oil may circulate through the resistors while much of the contamination from `dirty circuit breaker oil is excluded. This circulation of oil, of course, occurs through the openings in oating contacts 220l down through the resistor stack, and out through opening in contact 221.

A further important advantage of the resistor arrangement is that the unit assembly may be easily connected and removed from the interrupter structure proper, thus substantially simplifying assemibly and maintenance.

A still further advantage of the novel resistor structure lies in the compact subassembly permitted by the use of the snap-rin-gs 224 and 225 which capture the floating 10 contacts 220 and 221 respectively to maintain theV integrity of the subassembled resistor.

Although this invention has been described with respect to its preferred embodiments, it should' be understood that many variations and modifications will now be obvious to those skilled in the art, and it is preferred therefore that the scope of the invention be limited not by the specific disclosure herein but only by the appended claims.

The embodiments of the invention in which an exclusive privilege or property is claimed are defined as follows:

1. A check-valve structure for the interrupter structure of an oil circuit breaker; said interrupter structure including an interrupter container, stationary contact means secured within said interrupter container, movable contact means movable into and out of engagement with respect to said stationary contact means and a pump means for forcing uid under pressure into said interrupter container responsive to movement of said movable contact to a disengaged position with respect to said stationary contact; said pump means including a piston and a cylinder; said cylinder communicating with the interior of said interrupter container; said piston having a plurality of openings circularly distributed around an end wall thereof; said piston having an annular check-valve connected to said end Wall movable into and out of sealing engagement with said circularly distributed openings; said annular check-valve being moved to its said sealing engagement position responsive to the operation of said movable contact to said disengaged position; said circularly distributed openings forming a vchannel for the ow of oil into and out of said interrupter container when said movable contact is in engagement with said stationary contact; and a plate member for enclosing the top of said interrupter container and the bottom of said cylinder; said plate having second openings therein for permitting fluid flow from said interrupter chamber to said cylinder; and a second check valve; said second check valve being mounted with respect to said plate for movement into and out of sealing engagement with respect to said second openings; said second check valve being movable into its said sealing engagement position responsive to a higher pressure in said interruptercontainer than in said cylinder; and said second check valve being normally in an open position to normally permit circulation of oil therethrough.

2. The `device substantially as set forth in claim; 1 wherein said second openings are circularly arranged in said plate; said second check Valve comprising a second annular member en-gageable with each of said second openings.

3. The device substantially as set forth in claim 1 wherein said stationary contact means is directly secured to a centrally located portion on the bottom of said plate; said second openings surrounding said stationary contact means; said second annular member being carried on said stationary contact means.

References Cited by the Examiner UNITED STATES PATENTS 2,271,989 2/1942 Prince 200-150 2,606,262 8/ 1952 Barlett 200-150 2,619,568 1l/1952 Leeds 20G-150 FOREIGN PATENTS 735,884 8/1955` Great Britain.

ROBERT K. SCHAEF-ER, Primary Examiner. R. S. MACON, Examiner. 

1. A CHECK-VALVE STRUCTURE FOR THE INTERRUPTER STRUCTURE OF AN OIL CIRCUIT BREAKER; SAID INTERRUPTER STRUCTURE INCLUDING AN INTERRUPTER CONTAINER, STATIONARY CONTACT MEANS SECURED WITHIN SAID INTERRUPTER CONTAINER, MOVABLE CONTACT MEANS MOVABLE INTO AND OUT OF ENGAGEMENT WITH RESPECT TO SAID STATIONARY CONTACT MEANS AND A PUMP MEANS FOR FORCING FLUID UNDER PRESSURE INTO SAID INTERRUPTER CONTAINER RESPONSIVE TO MOVEMENT OF SAID MOVABLE CONTACT TO A DISENGAGED POSITION WITH RESPECT TO SAID STATIONARY CONTACT; SAID PUMP MEANS INCLUDING A PISTON AND A CYLINDER; SAID CYLINDER COMMUNICATING WITH THE INTERIOR OF SAID INTERRUPTER CONTAINER; SAID PISTON HAVING A PLURALITY OF OPENINGS CIRCULARLY DISTRIBUTED AROUND AN END WALL THEREOF; SAID PISTON HAVING AN ANNULAR CHECK-VALVE CONNECTED TO SAID END WALL MOVABLE INTO AND OUT OF SEALING ENGAGEMENT WITH SAID CIRCULARLY DISTRIBUTED OPENINGS; SAID ANNULAR CHECK-VALVE BEING MOVED TO ITS SAID SEALING ENGAGEMENT POSITION RESPONSIVE TO THE OPERATION OF SAID MOVABLE CONTACT TO SAID DISENGAGED POSITION; SAID CIRCULARLY DISTRIBUTED OPENINGS FORMING A CHANNEL FOR THE FLOW OF OIL INTO AND OUT OF SAID INTERRUPTER CONTAINER WHEN SAID MOVABLE CONTACT IS IN ENGAGEMENT WITH SAID STATIONARY CONTACT; AND A PLATE MEMBER FOR ENCLOSING THE TOP OF SAID INTERRUPTER CONTAINER AND THE BOTTOM OF SAID CYLINDER; SAID PLATE HAVING SECOND OPENINGS THEREIN FOR PERMITTING FLUID FLOW FROM SAID INTERRUPTER CHAMBER TO SAID CYLINDER; AND A SECOND CHECK VALVE; SAID SECOND CHECK VALVE BEING MOUNTED WITH RESPECT TO SAID PLATE FOR MOVEMENT INTO AND OUT OF SEALING ENGAGEMENT WITH RESPECT TO SAID SECOND OPENINGS; SAID SECOND CHECK VALVE BEING MOVABLE INTO ITS SAID SEALING ENGAGEMENT POSITION RESPONSIVE TO A HIGHER PRESSURE IN SAID INTERRUPTER CONTAINER THAN IN SAID CYLINDER; AND SAID SECOND CHECK VALVE BEING NORMALLY IN AN OPEN POSITION TO NORMALLY PERMIT CIRCULATION OF OIL THERETHROUGH. 